A related-art process for fabricating a semiconductor includes forming a plurality of semiconductor elements on a circuit pattern formation surface of a semiconductor wafer and subsequently slicing (cutting) the semiconductor wafer, in a mechanical manner, so as to separate the semiconductor elements from each other. A fabricated semiconductor chip is bonded to a leadframe, a substrate, and the like, by means of an epoxy-resin-based liquid adhesive. However, a film-shaped adhesive called a die attach film (DAF) which is easy to handle in connection with a thin semiconductor chip has recently been used.
The die attach film is affixed to a rear surface of a semiconductor wafer (i.e., a surface opposite to a circuit pattern formation surface) before mechanical dicing of the semiconductor wafer and mechanically sliced in conjunction with the semiconductor wafer. For the reason, each of sliced semiconductor chips has the die attach film which is essentially equal in size to the semiconductor chip, and the semiconductor chips can be bonded, just as they are, to a leadframe, a substrate, and the like.
Plasma dicing which is a dicing technique imposing no load on a semiconductor wafer has recently gained attention as a technique which enables performance of dicing operation without imposing a bend, warpage, and the like, on a semiconductor wafer has been slimmed down to a thickness of tens of micrometers or thereabouts. Plasma dicing includes forming boundary trenches—which partition semiconductor elements—in a resist film formed over the semiconductor wafer and etching (engraving) a surface of the semiconductor wafer exposed through the boundary trenches by means of a fluorine-based gas plasma, thereby separating the semiconductor wafer into semiconductor chips. In addition to a photolithography method for transferring a mask pattern—into which boundaries among semiconductor elements (areas among adjacent semiconductor elements) are to be etched—by means of exposure and developing the thus-exposed mask pattern, a method for cutting the resist film by means of emitting a laser beam to boundaries among semiconductor elements has been known in connection with formation of boundary trenches (Patent Document 1). Since the latter method does not need use of an expensive exposure transfer apparatus, plasma dicing can be carried out at low cost. Using a die attach film in lieu of a resist film has also been proposed (Patent Document 2).
[Patent Document 1] JP-A-2005-191039
[Patent Document 2] JP-A-2006-210577
[Patent Document 3] JP-A-2005-203401
[Patent Document 4] JP-A-2005-294535